Two-component bracket and drive washer combination for automatically setting an air gap

ABSTRACT

A two-component bracket and drive washer combination which provides secure holding of a magnetic sensor while automatically setting an optimal air gap, wherein operation is very quick, easy and reliable and wherein the air gap setting is precisely repeated each time a magnetic sensor is replaced or re-installed. A main bracket component has an aperture and a drive wall at one end of the aperture. A sensor body is connected to the main bracket component and is allowed to touch a reluctor. A reaction bracket has a reaction wall in the aperture opposite the drive wall and is restrained from moving. A drive washer is provided with teeth having a pitch whereby as the washer is pressed between the drive and reaction walls along a transverse axis, the main bracket component is forced to move along a longitudinal axis, thereby moving the sensor body in relation to the reluctor an amount precisely equal to a desired air gap.

TECHNICAL FIELD

The present invention relates to brackets for holding a first objectwith respect to a second object. More particularly, the presentinvention relates to a bracket for precisely locating a sensor relativeto an object to be sensed. Still more particularly, the presentinvention relates to a two-component bracket and drive washercombination, wherein facial interaction between the two-componentbracket and the drive washer as they are brought together along atransverse axis results in one component of the two-component bracketmoving a precisely predetermined distance relative to the center of thedrive washer along a longitudinal axis normal to the transverse axis,thereby automatically setting an air gap.

BACKGROUND OF THE INVENTION

Magnetic sensors operate on the principle of detecting magnetic fluxdensity modulation caused by the movement of appropriately configuredreluctors (or targets). The magnetic sensor must be affixed very closeto the reluctor since its sensitivity decreases very rapidly with thesize of the air gap between the reluctor and the magnetic sensor. Inmost automotive applications, for example, the air gaps are on the orderof 0.3 to 1.75 mm. Over such a range of air gaps, the sensor outputsignal decreases more than ten times. The signal attenuation at largeair gaps makes the sensor operation more prone to noise induced failuresas well as less accurate in detecting the elements of the reluctor as itspins in relation to the magnetic sensor. Both of these factors areoften unacceptable in critical engine control and diagnosticapplications.

It may at first glance appear that there would be no problem whatsoeverto choose and achieve an appropriate air gap between the magnetic sensorand the reluctor. However, in the majority of production cases, thestack-up of tolerances of the many different components randomlyinfluence the net size of the air gap, which consequently precludesachieving, at each assembly, a precisely predetermined air gap by mereassembly of the parts. As a result, because of the random variationscaused by accumulation of tolerances, mere assembly of the parts risksdamaging interference between the magnetic sensor and reluctor on theone hand, and inaccurate readings associated with too large an air gapon the other hand. To lessen all the tolerances so that mere assemblyassures, at each assembly, the optimum air gap is physically unrealisticand involves inordinate costs associated with manufacturing such preciseparts.

The majority of magnetic sensors used in automotive applications involvenon-adjustable air gap placement, wherein the stack-up of tolerancescauses deviation from the optimal air gap. For example, a rigid bracketis affixed to the body of a magnetic sensor. The magnetic sensor isplaced into a sensor port in the engine block, and the bracket isbolted, via a bolt hole in the bracket, to a threaded mounting hole in amounting surface of the engine block. When the bracket is bolted, thelength of the sensor body from the bolt hole of the bracket to thesensor tip determines the air gap with respect to the reluctor, whichair gap is affected by the stack-up of tolerances. Even though subjectto tolerance related placement inaccuracy, this structural mountingmethodology is used widely because of the simplicity of the hardware,and ease of assembly and service.

In situations where air gap variation cannot be tolerated, the air gapis preset during magnetic sensor installation by means of an adjustablebracket, often referred to as a “side mount” bracket. The adjustabilityof side mount brackets resides in a bolt slot which allows for thebracket to be adjusted along the slot elongation relative to thethreaded mounting hole of the mounting surface.

In one form of operation of side mount bracket, the sensor body isplaced into the sensor port of the engine block such that the sensor tipis allowed to touch the surface of the reluctor, and then it iswithdrawn a distance equal to the predetermined optimum air gap. Thismethod is more time consuming and is error prone.

In another form of operation of side mount bracket, a sacrificial layerof soft abradable material is placed onto the sensor tip, wherein thethickness of the sacrificial layer is equal to the optimum air gap. Now,the installer need merely place the sensor body into the sensor portuntil the sensor tip touches the reluctor, and then tighten the bolt onthe mounting surface with the sensor body retained at this position.During initial rotation of the reluctor, the sacrificial layer mayabrade due to reluctor runout or differential thermal expansion withoutdamage being incurred to the sensor body or the reluctor. Thesacrificial layer may be either attached to the sensor body or be a partthereof, such as a protuberance, provided the sensor body is of a softmaterial. However, in the event the magnetic sensor must bere-installed, the abraded sacrificial layer will not be able to againprovide position location as it was able to do when unabraded.Therefore, before dismounting the magnetic sensor, the bracket must bemarked to indicate the correct position of the sensor body relative tothe bracket so that when the new magnetic sensor is re-installed itsposition on the bracket can be sighted—not an exact procedure. In anyevent, should the sacrificial layer be exposed to a lubricating oil, theoil spray may carry the abraded debris into oil passageways.

In the prior art, it is known to precisely adjust the air gap using athreaded sensor body and threaded sensor port. This structure isgenerally used exclusively with magnetic sensors having a single sensingelement and having sensing capability unaffected by sensor rotationaround its longitudinal axis. In this approach, the sensor tip isbrought into touching engagement with the reluctor, and then the sensorbody is rotated a predetermined angular amount, wherein the pitch angleof the threads raises the tip a distance equal to the optimum air gap.However, most automotive magnetic sensors contain more than one sensingelement and are designed to operate at only one particular angularsetting around the sensor axis. Consequently, a threaded sensor bodywould need to be adjusted in whole revolution steps (ie., 360 degrees)and air gap adjustment would then be in steps of the thread pitch. Whilethe use of a sufficiently small pitch may render the air gap settingresolution adequate, many sensors are precluded from rotation due togeometrical interferences.

Accordingly, what is needed in the art is a structure for holding amagnetic sensor which allows easy and quick re-installation and removalof the magnetic sensor, and provides for automatic setting of an optimalair gap.

SUMMARY OF THE INVENTION

The present invention is a two-component bracket and drive washercombination which provides secure holding of a magnetic sensor whileautomatically setting an optimal air gap, wherein operation is veryquick, easy and reliable and wherein the air gap setting is preciselyrepeated each time a magnetic sensor is replaced or re-installed.

A two-component bracket is provided in the form of a main bracketcomponent and a reaction bracket component, wherein the reaction bracketcomponent is located in side-by-side relation to the main bracketcomponent and interconnected therewith so as to be slidable in relationthereto along a longitudinal axis. The main bracket component isprovided with a relatively large aperture, wherein a drive wall of themain bracket component is located on one side thereof. The reactionbracket component has a reaction wall located in the aperture oppositethe drive wall. The drive and reaction walls at the aperture mutuallyresult in a collective opening elongated along the longitudinal axis.

The drive washer is knurled, wherein the knurling of the sidewallthereof provides a plurality of teeth having a predetermined pitchangle, while the drive and reaction walls are smooth. The teeth of thesidewall may be provided in any suitable form, such as for examplesplines, serrations, cutting ridges or cutting surfaces arranged alongthe pitch angle. A slight draft (ie., conical shape) of the drive washeris preferred to facilitate initial insertion of the drive washer intothe collective opening with respect to abutment with the drive andreaction walls. In this regard, the drive washer has an initial bracketengagement surface and the draft commences at said initial bracketengagement surface.

The drive washer and spacing between the drive and reaction walls aredimensioned so that when the drive washer is inserted into thecollective opening, the drive and reaction walls tightly abut the teethof the drive washer. Since the drive washer teeth are hard in relationto the drive and reaction walls, the teeth inscribe correspondinggrooves into the smooth drive and reaction walls as the drive washer ispressed into the collective opening along a transverse axis. In thisregard, it is preferred for the reaction wall to be harder than thedrive wall.

The reaction bracket component has an affixment hole generally centrallypositioned with respect to the aperture and is secured to a non-movablearticle, such as for example a mounting surface, via a bolt passingthrough the affixment hole and threading into a threaded bore at themounting surface. The drive washer has a central hole through which thebolt also passes.

Both the main bracket component and the reaction bracket component arerestrained from rotating about the bolt, but the drive washer is freelyrotatable about the bolt. The main bracket component is freely movablealong the longitudinal axis, but is restrained from moving along thetransverse axis. The reaction bracket component is restrained frommoving along both the longitudinal and transverse axes.

As the bolt is tightened, the drive washer teeth engage the smooth driveand reaction walls, whereupon corresponding grooves are inscribedthereinto. In this regard, as the drive washer moves into the collectiveopening, the drive washer rotates on the bolt in response to the pitchof the teeth as the teeth cut into the reaction wall. Further in thisregard, the drive wall is caused to move along the pitch of the teethand further to move in response to the rotation of the drive washer.

In operation with respect to installation of an automotive magneticsensor with respect to a reluctor, the magnetic sensor is affixed to themain bracket component. An installer places the sensor body of themagnetic sensor into the sensor port of the engine block such that thesensor tip touches the surface of the reluctor. The bolt carrying thedrive washer is loosely threaded into a threaded bore at the mountingsurface until the sidewall of the drive washer touches the drive andreaction walls. The installer continues to thread the bolt into thethreaded bore, thereby causing the drive washer to be pressed into thecollective opening along the transverse axis. As the drive washerpenetrates into the collective opening, the toothed sidewalls inscribethe smooth drive and reaction walls, resulting in the drive washersliding parallel to and along the teeth at each of the drive andreaction walls. In this regard, the tooth and groove interaction at thereaction wall results in a rotation of the drive washer on the boltsince the reaction bracket cannot move.

Accordingly, as the drive washer moves into the collective opening alongthe transverse axis, the main bracket component is caused to move alongthe longitudinal axis relative to the bolt based upon firstly the toothto groove interaction at the drive wall and secondly based upon therotation of the drive washer. This duality of interaction of the drivewasher at the drive wall results in the main bracket component movingalong the longitudinal axis at twice the rate as would be provided bythe pitch angle alone. The distance of relative movement along thelongitudinal axis is given by: 2*(D*tan(A))=G, wherein D is the depth ofpenetration of the drive washer into the collective opening along thetransverse axis, A is the pitch angle of the teeth, and G is thedistance of movement of the main bracket component along thelongitudinal axis and is equal to the desired optimum air gap.

Now, should the magnetic sensor require servicing, it can be removed andre-installed, or a new magnetic sensor can be installed in its place,using the installation procedure outlined above. In each case, theoptimum air gap will be precisely achieved automatically. In the case ofre-installation, the original installation will have resulted in thedrive washer and two-component bracket becoming lodged together so as toresist mutual separation. Consequently, the magnetic sensor can bere-installed using the lodged drive washer and two-component bracketcombination and yet the same air gap will pertain because the originalrelative position between the mounting bolt and the two-componentbracket will be maintained.

Accordingly, it is an object of the present invention to provide astructure for holding one object relative to a second object, wherein apreset distance of separation with respect to a third object isautomatically set.

It is a further object of the present invention to provide atwo-component bracket and drive washer combination wherein the facialinteraction between opposing walls of first and second bracketcomponents with the sidewall of the drive washer provides apredetermined movement of one of the first and second bracket componentsalong a longitudinal axis in response to pressing of the drive washerbetween the opposing walls along a transverse axis.

It is yet an additional object of the present invention to provide adrive washer and two-component bracket combination for preciselylocating a magnetic sensor relative to a reluctor, wherein the air gaptherebetween is automatically set independent of stack-up of partstolerances.

These, and additional objects, advantages, features and benefits of thepresent invention will become apparent from the following specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partly sectional side view of a first form of thetwo-component bracket and drive washer combination according to thepresent invention, shown in a typical environment of operation wherein amagnetic sensor is spaced from a reluctor a distance equal to an optimumair gap.

FIG. 2 is a partly sectional side view of the first form of thetwo-component bracket and drive washer combination according to thepresent invention, shown in operation.

FIG. 3 is a partly sectional top plan view of a second form of thetwo-component bracket and drive washer combination, shown in operation.

FIG. 4 is a partly sectional side view of the second form thetwo-component bracket and drive washer combination, shown at apreliminary stage of operation.

FIG. 5 is a partly sectional top plan view of the second form of thetwo-component bracket and drive washer combination, now shown at aninitial stage of operation thereof.

FIG. 6 is a partly sectional side view of the second form of thetwo-component bracket and drive washer combination, shown at the initialstage of operation.

FIG. 7 is a partly sectional top plan view of the second form of thetwo-component bracket and drive washer combination, now shown at a finalstage of operation thereof.

FIG. 8 is a partly sectional side view of the second form of thetwo-component bracket and drive washer combination, shown at the finalstage of operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the Drawings, FIGS. 1 and 2 generally depict a firstform of the two-component bracket and drive washer combination 10according to the present invention in an exemplar environment ofoperation, wherein the two-component bracket and drive washercombination serves to locate a magnetic sensor 12 with respect to areluctor 14. In this regard, the magnetic sensor 12 has a sensor body 16which includes a sensor tip 18. The sensor tip 18 extends into a sensorport 20 of an engine block 22 and is spaced from the reluctor 14 apredetermined distance equal to an optimum air gap G which providesoptimal sensing performance by the magnetic sensor of magnetic fieldvariations as the reluctor spins.

A two-component bracket 24 is composed of a main bracket component 26and a reaction bracket component 28. The main bracket component 26 isconnected to the sensor body 16, as for example in perpendicularrelation analogous to a flag on a flag pole. The main and reactionbracket components 26, 28 are located in side-by-side relation to eachother and interconnected therebetween so as to be slidable in relationto each other along a longitudinal axis. The interconnection isachieved, for example, via elongate holes 30 in the main bracketcomponent 26 which receive therethrough bent over tabs 32 of thereaction bracket component 28, wherein the holes 30 are elongated alonga longitudinal axis L.

The main bracket component 26 is provided with a relatively largeaperture 34, wherein a drive wall 36 of the main bracket component islocated on one side thereof. The reaction bracket component 28 has areaction wall 38 located in the aperture 34 opposite the drive wall 36.The drive and reaction walls 36, 38 are oriented parallel to thelongitudinal axis L, and mutually result in a collective opening 40 thatis elongated along the longitudinal axis.

A drive washer 42 has a knurled sidewall 44, the knurling of whichprovides a plurality of teeth 46 having a predetermined pitch angle A(see FIG. 2). The teeth 46 of the sidewall 44 may be provided in anysuitable form, such as for example splines, serrations, cutting ridgesor cutting surfaces arranged along the pitch angle. A slight draft (ie.,conical shape) of the drive washer 42 is preferred to facilitate initialinsertion of the drive washer into the collective opening 40 withrespect to abutment with the drive and reaction walls 36, 38.

The drive washer 42 and spacing between the drive and reaction walls 36,38 are dimensioned so that when the drive washer is inserted into thecollective opening 40, the drive and reaction walls tightly abut theteeth 46 of the drive washer. Since the teeth 46 are hard in relation tothe drive and reaction walls 36, 38, the teeth inscribe correspondinggrooves into the smooth drive and reaction walls as the drive washer ispressed into the collective opening 40 along a transverse axis T. Inthis regard, it is preferred for the drive wall 36 to be softer than thereaction wall 38; for example, the drive wall may be composed of plasticwhile the driven wall may be composed of metal. Preferably, the drivewasher 42 is composed of a hard metal.

The reaction bracket component 38 has an affixment hole 48 generallycentrally positioned with respect to the aperture 34 and is secured to anon-movable article, such as for example a mounting surface 50 of theengine block 22, via a bolt 52 passing through the affixment hole andthreading into a threaded bore 54 at the mounting surface. The drivewasher 42 has a central hole 56 through which the bolt 52 also passes. Aflat disk washer 45 is preferably located between the head of the bolt52 and the drive washer 42.

Both the main bracket component 26 and the reaction bracket component 28are restrained from rotating about the bolt 52 via the sensor body 16being received into the sensor port 20; however, the drive washer 42 isfreely rotatable about the bolt. The main bracket component 26 is freelymovable along the longitudinal axis L, but is restrained from movingalong the transverse axis T by tightening action of the bolt. Thereaction bracket component is restrained from moving along both thelongitudinal and transverse axes L, T by virtue of the bolt having agenerally snug fit with respect to the affixment hole 48 and thetightening of the bolt.

In operation, an installer places the sensor body 16 into the sensorport 20 such that the sensor tip 18 touches the surface of the reluctor14. The bolt 52 carrying the drive washer 42 is loosely threaded intothe threaded bore 54 of the mounting surface until the teeth of thesidewall of the drive washer touch the drive and reaction walls 36, 38.The installer continues to thread the bolt 52 into the threaded bore 54,thereby causing the drive washer 42 to be pressed into the collectiveopening 40 along the transverse axis T.

Referring now more particularly to FIG. 2, as the bolt 52 is tightened,the teeth 46 of the drive washer 42 engage the smooth drive and reactionwalls 36, 38, whereupon corresponding grooves 58 are inscribedthereinto. In this regard, as the drive washer 42 moves into thecollective opening 40, the drive washer rotates on the bolt 52 inresponse to the pitch angle A of the teeth 46 as the teeth cut into thereaction wall 38. Further in this regard, the drive wall 36 is caused tomove along the pitch angle A of the teeth 46 and further to move inresponse to the rotation of the drive washer. Accordingly, as the drivewasher 42 moves along the transverse axis T, the main bracket component26 moves along the longitudinal axis L in relation to the bolt 52 attwice the rate as that provided by the pitch angle alone. The distanceof relative movement of the main bracket component 26 along thelongitudinal axis L to provide the air gap, G, is determined by thedepth of penetration of the drive washer 42 into the collective opening40 along the transverse axis T and the pitch angle A of the teeth 46, aswill be discussed in greater detail hereinbelow.

Referring now to FIGS. 3 through 8 the second form of the two-componentbracket and drive washer combination 10′, which is most preferred, willbe detailed. For the sake of brevity, same numerals will designate sameparts and primed numerals will designate analogous parts to those partsdesignated by numerals in FIGS. 1 and 2, so that a fully repetitivedescription is obviated for a full understanding thereof.

The two-component bracket 24′ is composed of a main bracket component26′ and a reaction bracket component 28′ and the main bracket componentis connected to the sensor body 16. The main and reaction bracketcomponents 26′, 28′ are interconnected by upper and lower overhangs 60,62 which interferingly engage the main bracket component 26′ withrespect to the transverse axis T, yet allow slidable movement along thelongitudinal axis L. A chamfer 64 of the main bracket component 26′ ispreferably provided for interfacing with the lower overhang 62.

The reaction wall 38′ is formed at one side of the aperture 34′, whereinthe drive wall 36′ is located on the other side thereof by virtue of acutaway section 65 of the reaction bracket component 28′. The drive andreaction walls 36′, 38′ are oriented parallel to the longitudinal axisL, and mutually result in the collective opening 40′.

The drive washer 42 is as described hereinabove. The drive washer 42 andspacing between the drive and reaction walls 36′, 38′ are dimensioned sothat when the drive washer is inserted into the collective opening 40′,the drive and reaction walls tightly abut the teeth 46 of the drivewasher. Since the teeth 46 are hard in relation to the drive andreaction walls 36′, 38′, the teeth inscribe corresponding grooves intothe smooth drive and reaction walls as the drive washer is pressed intothe collective opening along a transverse axis T, as describedhereinabove; and the hardness relationships are as previously described.

The affixment hole 48′ in the reaction bracket component 38′ receivesthe bolt 52, as previously described. Both the main bracket component26′ and the reaction bracket component 28′ are restrained from rotatingabout the bolt 52 via the sensor body 16 being received into the sensorport 20 (see FIG. 5); however, the drive washer 42 is freely rotatableabout the bolt. The main bracket component 26′ is freely movable alongthe longitudinal axis L, but is restrained from moving along thetransverse axis T by tightening action of the bolt. The reaction bracketcomponent 28′ is restrained from moving along both the longitudinal andtransverse axes L, T by virtue of the bolt having a generally snug fitwith respect to the affixment hole 48 and the tightening of the bolt.

Referring now to FIGS. 5 through 8, operation will be described withrespect to setting an air gap.

As shown at FIG. 5, an installer places the sensor body 16 into thesensor port 20 such that the sensor tip 18 touches the surface of thereluctor 14. As shown at FIG. 6, the bolt 52 carrying the drive washer42 is loosely threaded into the threaded bore 54 of the mounting surfaceuntil the sidewall of the drive washer 42 touches the drive and reactionwalls 36′, 38′. The installer continues to thread the bolt 52 into thethreaded bore 54, thereby causing the drive washer 42 to be pressed intothe collective opening 40′ along the transverse axis T.

As shown comparatively by reference to FIGS. 6 and 8, as the bolt 52 istightened, the teeth 46 of the drive washer 42 engage the smooth driveand reaction walls 36′, 38′, whereupon corresponding grooves 58 areinscribed thereinto. In this regard, as the drive washer 42 moves intothe collective opening 40′, the drive washer rotates on the bolt 52 inresponse to the pitch angle A of the teeth 46 as the teeth cut into thereaction wall 38′. Further in this regard, the drive wall 36′ is causedto move along the pitch angle A of the teeth 46 and further to move inresponse to the rotation of the drive washer. Accordingly, as the drivewasher 42 moves along the transverse axis T, the main bracket component26′ moves along the longitudinal axis L in relation to the bolt 52 attwice the rate as that provided by the pitch angle alone. As shown bycomparison between FIGS. 5 and 6 and FIGS. 7 and 8, the distance ofrelative movement of the main bracket component 26′ along thelongitudinal axis L is given by: 2*(D*tan(A))=G, wherein D is the depthof penetration of the drive washer 42 into the collective opening 40′along the transverse axis T, A is the pitch angle of the teeth 46, and Gis the distance of movement of the main bracket component along thelongitudinal axis L.

Now, should the magnetic sensor require servicing, it can be removed andre-installed, or a new magnetic sensor can be installed in its place,using the installation procedure outlined above. In each case, theoptimum air gap will be precisely achieved automatically. In the case ofre-installation, the original installation will have resulted in thedrive washer and two-component bracket becoming lodged together so as toresist mutual separation. Consequently, the magnetic sensor can bere-installed using the lodged drive washer and two-component bracketcombination and yet the same air gap will pertain because the originalrelative position between the mounting bolt and the two-componentbracket will be maintained.

It should be noted that by the term “smooth” as used herein is meantthat the surface is able to accept inscribing by the teeth as describedhereinabove, whether or not the surface is actually physically smooth.Indeed, it is sufficient for the teeth of the drive washer to engage thedrive and reaction walls. By “engage” is meant the teeth of the drivewasher inscribe the drive and reaction walls or follow wall teethalready present on the drive and reaction walls.

To those skilled in the art to which this invention appertains, theabove described preferred embodiments may be subject to change ormodification. Such change or modification can be carried out withoutdeparting from the scope of the invention, which is intended to belimited only by the scope of the appended claims.

What is claimed is:
 1. A two-component bracket and drive washercombination for automatically positioning a component of thetwo-component bracket along a longitudinal axis responsive to the drivewasher being moved relative to the two-component bracket along atransverse axis that is perpendicular to the longitudinal axis,comprising: a two-component bracket comprising: a main bracket componenthaving an aperture, said main bracket component having a drive wall atone side of said aperture; and a reaction bracket component interfacedin side-by-side relation to said main bracket component, wherein saidmain bracket component is slidable in relation to said reaction bracketcomponent along a longitudinal axis, said reaction bracket componenthaving a reaction wall located in said aperture opposite said drivewall, said drive and reaction walls being disposed parallel to thelongitudinal axis and mutually forming a collective opening at saidaperture; and a drive washer having tooth means for engaging said driveand reaction walls as said drive washer is received into said collectiveopening along a transverse axis; wherein said main bracket componentmoves parallel to said longitudinal axis as said drive washer movesparallel to said transverse axis.
 2. The two-component bracket and drivewasher combination of claim 1, further comprising means for driving saiddrive washer into said collective opening and for retaining saidreaction bracket component at a predetermined fixed position.
 3. Thetwo-component bracket and drive washer combination of claim 2, whereinsaid tooth means comprises teeth having a predetermined pitch anglerelative to the transverse axis; and wherein as said drive washer ispenetratingly received into said collective opening, said teeth inscribesaid drive and reaction walls thereby causing said main bracketcomponent to move in relation to said reaction bracket componentparallel to said longitudinal axis.
 4. The two-component bracket anddrive washer combination of claim 3, wherein said main bracket componentmoves in relation to said reaction bracket component according to 2*(Dtan(A))=G, wherein D equals a depth of penetration of said drive washerinto said collective opening along the transverse axis, wherein A equalsthe pitch angle, and wherein G equals a distance of movement of saidmain bracket component relative to said reaction bracket component alongthe longitudinal axis.
 5. The two-component bracket and drive washercombination of claim 4, wherein said pitch angle is an acute angle. 6.The two-component bracket and drive washer combination of claim 5,wherein said drive washer has an initial bracket engagement surface;further wherein said drive washer sidewall has a draft commencing atsaid initial bracket engagement surface.
 7. The two-component bracketand drive washer combination of claim 5, wherein said drive and reactionwalls are substantially smooth prior to said drive washer penetratinginto said collective opening.
 8. Apparatus for holding a sensor relativeto a first surface and automatically spacing the sensor from an article,comprising: a sensor having a sensor body; a main bracket componentconnected to said sensor body, said main bracket component having aaperture, said main bracket component having a drive wall at one side ofsaid aperture disposed parallel to the longitudinal axis; a reactionbracket component interfaced in side-by-side relation to said mainbracket component, wherein said main bracket component is slidable inrelation to said reaction bracket component along a longitudinal axis,said reaction bracket having a reaction wall located in said apertureopposite said drive wall, said reaction wall being disposed parallel tothe longitudinal axis, said drive and reaction walls mutually forming acollective opening at said aperture; a drive washer having a sidewall,said sidewall having tooth means for inscribing said drive and reactionwalls as said drive washer is penetratingly received into saidcollective opening along a transverse axis; and means for driving saiddrive washer into said collective opening and for retaining saidreaction bracket at a fixed position relative to said collectiveopening; wherein said tooth means comprises teeth having an acute pitchangle relative to the transverse axis, and wherein as said drive washeris received into said collective opening said teeth inscribe said driveand reaction walls thereby causing said main bracket component to movein relation to said reaction bracket component parallel to saidlongitudinal axis according to 2*(D*tan(A))=G, wherein D equals a depthof penetration of said drive washer into said collective opening alongthe transverse axis, wherein A equals the pitch angle, and wherein Gequals a distance of movement of said main bracket component relative tosaid reaction bracket component along the longitudinal axis.
 9. Theapparatus of claim 8, wherein said drive washer has an initial bracketengagement surface; further wherein said drive washer sidewall has adraft commencing at said initial bracket engagement surface.
 10. Theapparatus of claim 9, wherein said drive and reaction walls aresubstantially smooth prior to penetration of said drive washer into saidcollective opening.